Currently, the two most popular forms of contraception available for males are male condoms and vasectomies, as opposed to the wide range of birth control options available for females. Both of these forms of contraception are very effective at preventing pregnancy for a female partner (and, in the case of latex and polyurethane condoms, preventing the transmission of sexually transmitted infections); however, they do have some setbacks. Condoms can inhibit sexual spontaneity and have been said to decrease penile sensitivity. Vasectomies, which involve the cutting of the vas deferens to prevent sperm from traveling to the penis, allow for more spontaneity but are primarily irreversible. Scientists are currently utilizing a variety of chemicals and hormones to create new kinds of male birth control. The goal for this new type of contraception is to temporarily stop the passage of sperm to the vagina to prevent pregnancy in a way that is reversible and will not cause any long-term consequences (such as permanent sterilization).1

Types of Male Birth Control

There are currently many different methods of male birth control being researched and tested. Most of these methods involve slowing or stopping the production of sperm by interfering with some stage of its development, which would result in low enough sperm count to make pregnancy nearly impossible.2 Many of these methods are still in the early stages of development and require much more research, but with the hard work of scientists and adequate funding, new methods of male contraception could be on the market within the next five to ten years.

Hormonal Contraception

Most research involving male hormonal contraception seeks to manipulate testosterone levels. Testosterone is an important hormone that influences the production and transport of sperm in the male body. When the effects of this hormone are blocked, the testes do not produce healthy sperm, resulting in temporary sterilization.1

Pairing testosterone with other hormones such as progestin, GnRH, or androgens slows sperm production by suppressing the secretions of Luteinizing Hormone (LH) and Follicle Stimulating Hormone (FSH) from the pituitary gland.1 Luteinizing Hormone provokes the synthesis and secretion of testosterone, and FSH supports the maturation of sperm cells.3 Both of these hormones are important for proper sperm production—without them, sperm will not develop properly in the testes.2

Decreasing testosterone in the male body results in a lowered sexual desire. Combining testosterone and progesterone (a synthetic form of the female hormone progestin) is one way to counteract an inhibited libido. This combination of hormones does limit the production of testosterone in the testes but maintains regular levels of testosterone in the blood and elsewhere in the body.1

Male hormonal birth control could come in the form of pills, skin patches, monthly injections, or yearly skin implants. This attempt to prevent pregnancy by way of synthetic hormones has yielded negative side effects for volunteers including weight gain, blood clots, and a decrease in sex drive. The effectiveness of male hormonal contraception is still in question. Studies show that even while taking the hormone supplements, some males still produce enough testosterone to stimulate growth of adequate sperm to achieve pregnancy. More research is necessary to determine the reason for this variability and ensure consistent effects of these methods of contraception.

In March of 2016, a male contraceptive study produced by the World Health Organization (WHO) was stopped due to a large drop-out rate in participants. The treatment comprised of a shot containing two hormones (200-mg norethisterone enanthate combined with 1000-mg testosterone undecanoate); the injections aimed to lower sperm count. The study boasted a 96% effectiveness in preventing pregnancy in the participant’s partner. Despite the promising effectiveness of the hormonal treatment, the study was halted due to a significant number of complaints about side-effects.4

The study was conducted on 320 males around the world. The participants received shots every eight weeks. Their sperm count was lowered drastically and only a few participants impregnated their partners. The most frequently reported side effect of the treatment was severe acne. Some males complained of mood swings. One male reported severe depression and another committed suicide. The study stopped shortly after.4 The decision to halt the study led to controversy over gender inequality as many females report the same side effects of their birth control, yet it is still widely used. Many critics attribute the premature conclusion of the study to differences in the risk-reward decision process between males and females taking contraceptives. When females evaluate the decision to take a contraceptive, they weigh the potential side effects of the hormonal contraceptive against the risk of becoming pregnant as well as all responsibilities that follow. While males must still consider the side-effects of the hormonal medication, they do not run the risk of becoming pregnant themselves. Although males should always take some degree of responsibility, there are few policies (depending on location) that hold males accountable for impregnating a female. As such, the balances may be tipped away from the hormonal treatment for fear of the side-effects which can sometimes be impossible to avoid.4

Nonhormonal Contraception

RISUG®

Reversible Inhibition of Sperm Under Guidance (RISUG®) involves injecting a non-hormonal, nontoxic polymer gel into the vas deferens to physically block the passage of sperm to the penis. This gel not only serves as a plug in the vas deferens, but it also reacts with and destroys sperm upon contact.4 This method is effective almost immediately and can be reversed at any time with another injection that flushes out the gel.1 The procedure takes only about fifteen minutes, is minimally invasive, and is predicted to be affordably priced.5

Clinical trials of RISUG® have shown that sperm levels in males who received the injection dropped within a few days, and the effects could last for many years. Unfortunately, there has been little research conducted concerning the long-term effects of this contraceptive method, so it is unclear if the injection has any adverse side effects or health risks or if its reversal will completely restore sperm production.5 RISUG® is not currently on the market yet, and clinical studies accept only Indian males who live near the study sites.

Vasalgel

Although similar in concept, Vasalgel is different than RISUG. They are both gel polymers that are injected into the vas deferens and act by blocking the passage of sperm. For years, RISUG has been used in India but has not passed United States Food and Drug Administration (FDA) standards. The producers of RISUG claim the gel is electrically charged, which destroys sperm as it encounters the gel. Vasalgel manufacturers have not made similar statements. Vasalgel is formulated differently to better adhere to FDA guidelines in hopes that it will pass government health regulations and be readily available on the market. The goal of Vasalgel is to be a fully reversible, durable and effective method to prevent ejaculation of viable sperm. In studies conducted on rabbits, sperm flow was restored after a sodium bicarbonate solution was injected into the vas deferens to flush out the gel. Vasalgel is expected to enter human trials in 2017. Vasalgel’s producer claims that the product will be inexpensive and readily available for use by large populations. The developer hopes the product will be covered by insurance companies. Ideally, the cost of Vasalgel will be equivalent to a day or two of a person’s wage ($800) in the United States, and to be less than the cost of an intrauterine device, a form of long lasting contraceptive implanted in females.6

A obstacle to the development and sale of Vasalgel is that many large pharmaceutical companies already offer existing birth control options to females. This is a very profitable market. Vasalgel and other male contraceptives would disrupt the current paradigm and threaten to undermine a market that already provides a large source of revenue for the pharmaceutical companies. As a result, Vasalgel operates on crowdfunding and donations to raise funds to be utilized in order to bring the product to market.7

Clean Sheets Pill

The “Clean Sheets Pill” is appropriately named, as it suppresses a male’s semen release altogether. This pill relaxes longitudinal muscles at the same time that it contracts circular muscles in the penis to cut off the flow of semen. The male still experiences sensations of orgasm—the only difference is that there is no ejaculation. The fluid that is blocked from leaving the penis is reabsorbed into the body.5

The Clean Sheets method of contraception would most likely be administered in the form of a pill, which would be taken at least two to three hours before intercourse and last as long as a full day. It could also be administered in the form of a continuous-release implant in the skin. The Clean Sheets method is an important breakthrough because it could be a very effective way to reduce the spread of HIV and other STIs that are transmitted via semen. The difficulties in making this product ready for the market stem from the nature of the pill itself. The medication is derived from a blood pressure medication that has too many side effects to be considered a safe option for male contraceptive.8 This product is still very new and has not been subjected to the kind of research required to determine its effectiveness or long-term health consequences.5 In order to for this type of treatment to meet FDA standards and be sold on the market, a form of this medication needs to be developed that produces the same levels of effectiveness, but with less side effects. For this to happen, researchers claim they need an estimated $300,000 for testing. Potential sources of revenue are HIV research grants. HIV research grants are numerous and large enough to fund these male contraceptive studies, yet many grant foundations are unaware of the fact that this treatment can prevent the spread of HIV. If this medication can be labeled as a preventative measure against the spread of the lethal HIV virus, then it may earn priority in the eyes of many activists, government agencies, and philanthropic foundations.8

Non-Hormonal Pills

A number of substances have been identified as successful contraceptive methods and are undergoing research to determine their efficacy rates and possible toxicity. Among these are Retionoic-acid receptor (RAR) antagonists and Gandarussa.

RAR-antagonists inhibit vitamin A receptors in the testes, which results in infertility. This medicine resulted in reversible infertility in mice without any adverse health consequences. The drug is being subjected to more research to ensure that the effects of vitamin A deficiency are, in fact, only located in the testes. If the drug inhibited vitamin A uptake elsewhere in the body, the deficiency would severely compromise the immune system, causing major illness.5

Gandarussa is a plant grown in Indonesia that has been found to reduce male fertility by weakening the sperm’s ability to penetrate an ovum. Scientists are in the process of extracting a chemical from the plant to create an over-the-counter pill. Trials on previous volunteers resulted in 99% effectiveness. After two months of discontinued use, male fertility returned to normal. The only noted side effect was a potentially increased sex drive. The Indonesian government expects to have the pill on the market sometime soon, but it will likely take longer to gain approval in other countries.5

Ultrasound

Another potential option for a male contraceptive is an ultrasound. The treatment is painless, and takes about fifteen minutes. This technique works by destroying sperm with sound waves emitted from a device which is placed on the tests. The treatment targets the testes only so the side effects are mitigated compared to the wide spread effects of hormonal treatments. Ultrasound technology is widely available in medical centers around the world. In studies conducted by the University of North Carolina, researchers successfully achieved the desired effects of inhibiting spermatogenesis in rats. However, concerns are raised over the duration of the treatments effectiveness. In some studies, too many consecutive treatments produced permanent infertility in subjects.8

Advantages of New Male Contraceptive Methods

This sections serves describe a few of the benefits offered by male contraceptives.

Males would gain more control over their reproductive lives, and the rate of unplanned pregnancies could be reduced.

Partners could have twice or even triple the protection from pregnancy when male contraception is paired with female contraception or barrier methods.

Rates of sexually transmitted infection transmission may also decrease, as these contraceptive methods would require more males to attend annual checkups with a doctor. It is important to remember, however, that male and female condom use will still be the only method that directly prevents the spread of STIs.

Ideally, knowledge about these benefits would spread and encourage more people to discuss these options with their health-care provider.

Attitudes Toward New Male Contraception

It is a common misconception that heterosexual males would prefer to leave the burden of contraception to females rather than take control of it themselves. However, recent surveys have shown that although females are more enthusiastic about the idea of male contraception, many males around the world are similarly excited about male birth control. Some males reported that they wanted to take some of the responsibility off of female partners, while others stated that they simply wanted a more reliable form of birth control than condoms. Single males tend to want to avoid unplanned pregnancies, and married males are interested in birth control for many reasons, such as not being able to afford another child. About half of males report enthusiasm about trying a new form of birth control, but this percentage can vary from country to country. The good news is that there is enough interest to generate a significant amount of buyers.5

Concluding Remarks

Many consider birth control to be one of the most influential inventions in the history of mankind as it allowed both females and males to engage in penile-vaginal intercourse with significantly decreased chances of pregnancy. It marked the first time in human history that females gained control over their reproductive cycle. However, there is always room for improvement. Hormonal contraceptives have only been in use for nearly 50 years, and the consequences of hormones on the brain and body development have yet to be determined. This begs the question of how to improve upon existing methods. Several options such as Vasalgel, ultrasound, and non-hormonal birth control methods are studied by scientists world-wide in an effort to endow men with the same control over their reproductive cycle as well. These options promise the similar levels of success in preventing pregnancy while leaving hormonal levels unaltered. As beneficial as female hormonal birth control has been, it is time to open up the discussion about the next step in improving birth control methods.